hydro energy

Hydro Energy

Last Updated: January 18, 2024By

Did you know you can use hydro energy to generate electricity in a surprisingly large number of ways?

Apart from the well-known hydroelectric dam projects around the world, water can be used to generate electricity in a large number of ways.

Let’s explore the power of water!

What is hydro energy?

Hydro energy is energy generated by the flow or storage of water. It’s a free, renewable source of energy. The earth is more than 70% water and energy is available from waterfalls, rivers, tides, ocean currents and more!

Hydro energy works on the principle of water flowing over or through a turbine which rotates and generates electricity.

The large hydroelectric dams work in the same way – water is stored in the dam and flows through sluice gates to a second dam lower down. When the water flows to the lower dam the turbines in the dam wall generate electricity.

Hydroelectric dams provide critical energy for many countries, some of which are nearly 100% reliant on this form of electricity generation.

In a sense a hydroelectric dam is a massive battery of energy. The potential energy from the water (created by gravity) flows through pipes and is converted into kinetic energy (motion) which turns the turbines at the bottom of the dam wall and generates electrical energy. It’s weird to think of a water storage dam as a battery but it really just holds a bunch of energy until it is needed.

Types of hydro energy

We’ve looked at hydroelectric dams above but water can be used to generate electricity in many other ways too.

Small-scale hydroelectric dams are built on farms. A farmer will use electricity (generated by solar panels for example) to pump water uphill to a large dam. When the sun stops shining at night or if it’s cloudy the water can be released back downhill to a lower dam. The downhill flow of water turns water turbine which generates electricity. The same water can then be pumped back uphill to repeat the process.

Farmers can therefore use water as a way to store and generate electricity which can be used for the various farming activities.

The oceans are a massive source of energy. New developments include using deep ocean currents to generate electricity through floating hydro turbines.

Sea turbines can be positioned in currents or tidal areas to use the back and forth flow of water from tides (which is actually MOON energy if you think about it).

Water turbines can be set up in various locations:

  • Existing natural rivers with a constant flow throughout the year
  • Artificial canals created by diverting water from one place to another (which has potential ecological effects)
  • Building dams or weirs which store energy in the form of water for later use

In fact, water can be used in as many ways as people can imagine to store and produce energy.

Take a look at this where gold mines have been converted into hydroelectric storage facilities.

What are the advantages of hydro energy?

Energy from water:

  • Is clean and renewable
  • Does not result in carbon emission and climate change (unlike fossil fuel energy)
  • Works day and night
  • Is available as long as the water is available
  • Is more reliable than solar energy or wind energy

There are of course, also:

Disadvantages of hydro energy

  • Setting up a large scale hydroelectric project requires massive investment
  • The dam or diversion of water from one area to another might have severe negative effects on the existing ecosystem
  • Not all areas have access to water
  • Some areas just don’t have the space or necessary geography (slopes and mountains) for hydro energy
  • Hydro energy requires massive maintenance in the long term

Can I use hydropower for my home?

Small scale or micro hydro turbines (also known as a microhydropower system) uses existing water flowing through your property to create electricity. This is great if you are a farmer or own a small plot of land, but what about smaller homes in the city with no river flowing through your back yard?

The reality is that on a small scale you can store and generate some energy if you pump water up onto the roof into a reservoir or tank. This water can be released to flow down a pipe to turn a small generator – but the amount of electricity you will generate overall is very small.

Ultimately small scale hydropower is not sufficient to be considered viable for home use if there is no stream or creek present, and you should invest in solar panels and wind energy (is possible) to go off-grid or save on grid power.

You need at least a small stream to turn water turbines to generate any reliable or meaningful amount of hydro power. The amount of power produced depends on the rate of low of the water as well as the force with which that water is flowing.

Think about the old watermills that people have been using for centuries. They rely on a stream or river to turn the wheel.

In the same way, hydro power can only come from a sufficiently large source of flowing water.

Having said that, there are exciting developments in the technology of hydro water, including this micro turbine for water under a bridge in Japan:

For privacy reasons YouTube needs your permission to be loaded. For more details, please see our Privacy Policy.
I Accept


Can I build my own hydro power system and go off-grid?

The answer is definitely – if you live near a stream, waterfall or river. Many people are going off-grid an developing their own energy systems using minimal expense.

Energy Systems and Design in Canada create incredibly efficient micro-hydro machines that generate electricity from flowing water:


Their technology is designed to use natural water sources such as creeks, streams and rivers.

Water flows through a nozzle at high speed and then turns a turbine wheel which rotates the generator shaft.

Their flagship product, the Stream Engine, can generate up to 1 kilowatt but they have other products capable of producing even more.

Electrical energy produced depends on flow rate and pressure. The higher the head (or height) from which the water flows downhill the greater the pressure. You can have really high pressure if your slope is very steep, even if you have a small pipe.

Final thoughts on hydro

Have you set up your own hydro system? We’d love to hear from you and get your thoughts on how things are working out. Let us know in the comments below.

If you have the right terrain, good water flowing nearby and the right equipment, you can set up a great hydro electric system to give you constant, free energy.

Like this? Share it!

About the Author: Tony Lopes

Tony is the founder and editor of CleanVolts.co.za. He has completed solar certifications and courses through Green Solar Academy. Tony's goal is to see solar panels on every roof-top in South Africa and the adoption of EVs and renewable technology across the African continent.

Leave A Comment